Synthesis and consolidation behavior of Al/AlN composite powders by reactive RF thermal plasma spraying

•Al/AlN composite powders were synthesized by a new technique using RF plasma spraying.•Volume fraction of AlN was high in the outer layer of the formed composite powders.•Nano-particles were attached on the surfaces of the synthesized composite powders.•The attached Al and AlN nano-particles acted as a compaction accelerator.•The sintered as-sprayed powder compact had a higher hardness value.

Al/AlN composite powders were synthesized using a new technique based on reactive RF thermal plasma spraying, and an investigation of the microstructure and consolidation behavior of the synthesized Al/AlN composite powders revealed that the volume fraction of the AlN particles was higher on the outer layer. Numerous nano-particles were attached to the surface of the Al/AlN composite powders, and the effects that the nano-particles had on the consolidation of the Al/AlN composite powders are discussed herein. The attached nano-particles acted as a compaction activator, filling the vacant space among the Al/AlN composite powders during compaction. The as-sprayed and sintered powder compact had a higher hardness value than the ultra-sonicated and sintered powder compact due to a lower porosity in addition to the presence of hard AlN nano-particles.

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